Monthly Archives: March 2024

Mold Spores, Endospores and Exospores…what are the differences?

I think most of us are familiar with spores that mold produces, which act similarly to dandelion seeds that can be carried off by air currents to relocate and start growing new “plants” elsewhere.  However, there are similar terms using the word “spore” in the bacteria world that don’t always mean the same thing!   Here’s some explanation to clear things up.  

First of all, it’s good to get refreshed regarding the two major classes of bacteria,  “Gram-negative” and “Gram-positive”.  These classes are based on a test developed by scientist Christian Gram in 1884, which differentiates the bacteria using a purple stain.   According to webmd.com, bacteria either have a hard, outer shell, or a thick, mesh-like membrane called peptidoglycan.  The hard outer shell will resist the purple stain, and show up as a red color.  These are called “gram negative” because the purple stain did not show.  Bacteria with the peptidoglycan absorb the purple stain much more easily and are called “gram positive”.  Here is a diagram showing the differences in the cell walls between these two types:

Source: Difference Between Gram-Positive and Gram-Negative Bacteria

These differences in cell structure cause gram-positive bacteria to release toxins that are different from gram-negative bacteria, as we explained in our article What are Endotoxins and Exotoxins and where do they come from?

Here is a diagram from that article that’s helpful:

Source: Differences Between Exotoxins and Endotoxins

Here’s where it gets confusing, however, because the “Exo-” prefix associated with gram-positive bacteria, and “Endo-” with gram-negative bacteria only applies to their toxins.  Moving on to spores, bacterial “spores” usually refers to endospores, endospores are usually associated with gram-positive bacteria, and endospores aren’t formed the same way that mold spores are.  Let’s look at endospores first…  

Endospores are not tiny little “seeds” released by a gram-positive bacteria.  Instead, they are a hardened shell that forms inside a bacterial cell when it starts to sense that resources (food and water) are drying up.  This little endospore with its essential life-code inside is then left when the original bacterial cell dies, and the endospore is tough-as-nails while waiting for a better environment  to allow it to flourish and multiply again.  One author describes them as being harder than Bruce Willis to kill (in the movie Die Hard, of course)!   (Endotoxins or Endospores?)  Endospores exhibit no signs of life, however when the environment returns to a favorable state for bacterial growth the bacterial endospore will germinate and return to a normal state.  (What are Bacterial Endospores?)  So, unlike mold spores of which one mold cell can make thousands of spores, if not millions, only one gram-positive bacteria makes one endospore.  The tough outer layer of an endospore is actually called an exosporium, which makes it a little bit more confusing.

Exospores are more similar to mold spores and they are a form of bacterial reproduction.  Exospores are produced by the members of the phylum Actinobacteria (Actinomyces, Streptomyces, etc).  They form outside the bacterial wall and are released by “budding” when they separate from the bacterial wall.  Exospores are also resistant to destruction and do not show signs of life until their environments have sufficient water and nutrients for them to grow.  Here is a diagram showing the difference between endospores and exospores:

Source: Difference Between Endospore and Exospore

Here are some similarities between Endospores and Exospores:

• Endospore and Exospore both spores are produced under unfavorable environmental conditions.

• Endospore and Exospore both are unicellular and have a resistant structure.

• The process of making spores in both types of known as sporulation.

• Endospores and Exospores both are reproductive cells.

Now that we know WHAT they are, what is the danger of spore-forming bacteria?  Bacterial spores may be in the quiescent state for dozens or hundreds of years but after they appear in the favorable conditions of a human or animal organism, they turn into vegetative forms causing an infectious process. We wrote about these in our article “‘Sleeper’ bacteria spores are like mold spores”.  The greatest threat among the pathogenic spore-forming bacteria is posed by the bacterial agents of anthrax (B. anthracis), food toxicoinfection (B. cereus), pseudomembranous colitis (C. difficile), botulism (C. botulinum), and gas gangrene (C. perfringens). (Learning from Nature: Bacterial Spores as a Target for Current Technologies in Medicine (Review)) 

Endospores literally work inside our immune system to accomplish their deadly mission.  In the example of illness caused by anthrax, when these endospores are inhaled by a human or animal host, they are engulfed by macrophages and dendrite cells, which are immune cells that circulate in the lymphatic system.  Spores transition from endospores to active bacteria inside the phagocytes and dendrite cells, multiply, and produce toxins. In the lymph nodes, immune cell death takes place with subsequent bacterial invasion to the blood flow, active proliferation, and toxin production which mediates clinical manifestations of the infection, resulting in lethal outcome.  (Learning from Nature: Bacterial Spores as a Target for Current Technologies in Medicine (Review))  Sadly, animals like cows and sheep are also susceptible to anthrax, especially when grazing land is dry and the soil can be inhaled as dust, because these endospores are found naturally in the soil.  This was the case in Australia in February 2024 when 10 beef cattle died of anthrax poisoning and a similar number of sheep died from anthrax poisoning in 2023.

How do you get rid of Endospores and Exospores?

Endospores are one of the most resistant specialized dormant cells, being able to resist high temperature (up to 100 °C), ionizing radiation, chemical solvents and detergents.   Mature exospores produced by Streptomyces are more resistant to desiccation, low temperature and osmotic changes (changes in permeability) than vegetative (living) cells. However, they are less resistant to heat and desiccation than endospores.  (Multiple roads lead to Rome: unique morphology and chemistry of endospores, exospores, myxospores, cysts and akinetes in bacteria)  Killing endospores, then, represents the most difficult task.  Autoclaves for cleaning medical equipment are set to run at the proper time, pressure and temperature. Using an exposure time of at least 15 minutes and 15 PSI at 121 celsius usually kills endospores on durable medical equipment.  For entire rooms, however, sporicides are used at preset times (like biweekly or monthly).  (Endotoxins or Endospores?) Sporicides can be composed of toxic chemicals like phenol (a mutagen, which is a potential cancer risk); this is the chemical used in the popular Sporicidin Disinfectant Solution.  However, less harmful chemicals like Hydrogen Peroxide and Acetic Acid are also used.  The combination of those two compounds is Peroxyacetic Acid (PAA). Acetic acid is also known as vinegar and has that acidic smell; PAA also has a vinegar smell so that personal protective equipment like masks, goggles and gloves may be required to use them.  The majority of sporicides on the EPA’s Registered Antimicrobial Products Effective Against C. diff Spores [List K] are sodium hypochlorite (bleach).  Bleach is definitely something you want to avoid bringing into your home.    

There is a very non-toxic product on this endospore-killing list, however: hypochlorous acid.  Even though it sounds toxic and it’s related to bleach (which is sodium hypochlorite), hypochlorous acid is much safer as well as being a far superior disinfectant to bleach.  One of the most fundamental reasons for this is its pH. Hypochlorous acid exists at a near-neutral pH (5-7). Bleach resides at a highly-alkaline pH (8-13). The germ-killing properties of bleach are derived from the presence of hypochlorous acid. However, because of its high pH, the majority of the hypochlorous acid present in bleach ends up getting converted to hypochlorite, which is a less effective disinfectant.  (Hypochlorous acid versus bleach: What's the difference?)

Other strategies to killing endospores are mentioned in this paper according to the part of the endospore they target; here are some interesting ones:

• “Germinate to eradicate” involves tricking the endospore into reviving and then killing the vegetative cells, because the vegetative cells are easier to kill.  Triggers for spore germination include temperatures close to 37°C (98.6°F, sound familiar?), making water available to “rehydrate” the cell through its bacterial cell walls, and the availability of nutrients.  (Why Are Bacterial Spores Hard To Sterilize?)   However, warm water and gloppy nutrients are not at all suitable for your home’s surfaces!

• Alcohols and aldehydes like ethanol and gluteraldehyde can work against the inner membrane of the endospore, but glutaraldehyde (0.5%) can irritate nasal passages and eyes, as well as severely burn skin. 

• Enzymes like proteases can degrade the “coat” of the endospore and even induce germination, so that it is easier to kill. (Enzyme-driven bacillus spore coat degradation leading to spore killing)

• Dodecylamine, a yellow liquid with an ammonia like odor, kills spores of all species that have been tested, including Bacillus species and C. diff.; however, it’s toxic to humans and animals. 

The most important thing about killing spores is to make sure they are dead, or if they are not, to make sure they are damaged beyond being able to reproduce!   Unfortunately, only a lab can determine whether endospores are present (PCR test, by re-animating them, or using a special green staining technique), so don’t “guess” whether a DIY solution has taken care of them.  Using a non-toxic product from the EPA’s list K (like hypochlorous acid) and making sure you give it ample “residence time” (ie. read the usage instructions and don’t mop it up right away) will ensure that you don’t suffer from those tough endospores re-animating in your home or body.    Here are some additional tips:

• Clean regularly with non-toxic ingredients.  The less dust and dirt we allow to accumulate in our homes, the less microbe spores are lying around.  Check out our article on Tackling Dust in Your Home.

• The FDA states that over-the-counter antibacterial hand soaps don’t protect us from disease any better than regular soap and water.  The cleansing action happens in the thorough agitation of soap and water over hands, and a good rinse with water.  Many “antibacterial” soaps also contain ingredients, like triclosan, which can be harmful to us over time.  

• Since you can’t easily scrub and rinse items like your countertop or toilet seat with soap and water, however, different solutions need to be employed there.  Sure, you can get antibacterial cleaning sprays, but the same concerns apply: are they safe long-term?  Instead, opt for cleaners that are non-toxic and are less likely to create antibiotic resistance.  We’ve recommended the following cleaners for these reasons:

• Because hypochlorous acid is an oxidant, it leaves nothing behind for bacteria and viruses to create resistance to and therefore does not contribute to the superbug (multidrug-resistant organisms) dilemma.(The Role of Hypochlorous Acid in Managing Wounds: Reduction in Antibiotic Usage)   Hypochlorous is not bleach; in fact, it’s superior to bleach.  Some hypochlorous cleaners include Force of Nature and CleanSmart Daily Surface Cleaner

• Our all-purpose, non-toxic cleaner TotalClean combines both copper and iodine, and when they are combined, they produce peroxide!  In simple terms, the peroxide acts as an “oxidizing agent”, destroying the means for bacteria to take in oxygen and suffocating them.  

• Of course, change your HVAC filter regularly so that spores do not find their way to your air handler’s evaporator coil, where moisture can allow them to reactivate.  We’ve got some great filters with activated carbon and MERV 10-14 ratings (for more on MERV, check out our article HVAC filter changes are vital to your indoor air quality. 

• The technology in our bipolar ionizers like our Germ Defender, Upgraded Air Angel Mobile and Whole Home Polar Ionizer has been tested against bacteria such as E. coli, MRSA and C. diff (see test results here), so why not add them to your non-toxic cleaning arsenal as a passive way to keep the spores under control? 

PSA: How to quickly shut off water to your home, and systems that can do it automatically

Think quick: do you know where your home’s water shut-off valve(s) are?   Imagine for a moment that you hear the sound of water gushing in the kitchen, and walk in to find it pouring out from under the kitchen sink.  If it’s not the dishwasher or kitchen faucet, then the leak may be in the wall–what do you do?  

Emergency water leaks are a realistic scenario, and every year, 1 in 12 homes experience a leak.  That’s more often than burglary or fires!  (Plumbing Leak Facts)  Therefore, it should be top priority to find your home’s water shut-off valve right away, and show it to other family members/housemates so that they know what to do, too.  It’s a good idea to practice gently closing and opening these valves every so often so that you know they work.  We use the term “gently” because old plastic valves and old plastic lines can break if they are manipulated with too much force!  If they are in bad repair, it’s time to replace them (or call a plumber to replace them) asap.

There could be multiple main water shut-off valves.  They are typically: (Two methods to turn off your homes water supply)

1. In the main riser– this is where the water pipe comes out of the ground outside, and enters the home through the side.  If you live in a cold climate, there may not be an exposed valve outside to avoid freezing!
2. In the garage or basement.  Normally it’s in the wall next to the garage door. 
3. At the water meter box, you can use a meter key (special long-handled wrench) to shut off the water to the whole home.
4. If you live in an apartment, there is one valve that serves the whole apartment.  It’s usually near your hot water heater or in a utility closet.

If you know where the water is coming from and you can shut it off at a specific appliance, go for it!  Here are the locations of specific water supply valves throughout a home: (How to shut off water supply in an apartment)

• Toilets: Below and behind the toilet at the wall.  These can be ¼ turn valves or fully opening and closing valves.
• Refrigerator: You’ll need to pull out the refrigerator to access the valve that supplies the icemaker; it’s usually recessed in the wall.  These are usually ¼ turn valves.
• Dishwasher: look underneath the sink for a supply line that goes toward the dishwasher. 
• Kitchen and bathroom sinks: under the sink, there are usually two for hot and cold. 
• Washing machine: the valves should be about 2-3 feet off the floor behind or next to the machine in the wall. 
• Water heater:  first, shut off the gas or electricity to the water heater.  Then, shut off the water supply by closing the valve(s) on the lines coming into the water heater at the top.  Then, relieve pressure to the lines by opening a sink faucet.  You can also help the water heater to drain to an appropriate place (like outside) by connecting a garden hose to the drain valve on the side, and opening the valve.  (How To Turn Off a Leaking Water Heater)
• Showers and baths: if there is not an access panel in the opposite side of the wall where the shower/bath valves are located, go and shut off water at one of the main supply valves mentioned above.

Here’s a trick if the main shut-off valve(s) is not closing all the way, and water is continuing to come in at a reduced rate.  You can open the other faucets with drains in the home, like bathtub, sinks, etc., to relieve pressure at the leak until the plumber can get there.

Now that you know where your water supply valves are, you might want to consider automatic water shut-off options.  There are many systems that can shut off your whole home’s water supply, but they fall into 2 categories: moisture detection and flow sensing.  Basically, the water valve is shut off if the system senses water on the floor (via water detectors scattered around the home) or if the water flow in the main supply exceeds a pre-set user amount (water runs for too long).  Here are some pros and cons for these systems:

Here are some systems for each:

Leak Detection: We spoke about individual leak detectors in this article, but the systems below can also shut off water:

• Phyn ($50-579) offers leak detection via moisture-detecting “pucks” you can place around your home under sinks and other water appliances, but it also has a “smart water assistant” that can notify you of leaks via pressure waves in the system in both your hot and cold water lines.  It also has a “plumbing check” function to detect pinhole-size leaks.  The Phyn Plus will shut off your water in case leak parameters are exceeded. 
• YoLink has a variety of water leak sensors that connect to their hub and thus can be programmed to activate an automatic water shutoff valve that is connected to the same app.

Flow-sensing: 

• Water Hero ($900-1250): This is a whole-home system that is installed on the main water line just inside or outside (only in non-freezing climates) your home.  The motorized valve is installed by your plumber, and then it can be activated when you connect the unit to wi-fi and set up the water usage parameters for your home online.  If the water usage exceeds the parameters you set (for example, for 20 minutes continuously), the valve shuts, limiting water leakage in the home.
• FloLogic ($2000-2900): This is also a whole-home system that is installed on the water main line, indoors or outdoors (outdoors with precipitation protection).  It has a more sophisticated flow sensor; FloLogic’s EverWatch™ leak sensing technology can see leaks in real time starting a ½ ounces per-minute (about a tablespoon).  Normal water use happens in intervals. Leaks are constant. Once flow begins, FloLogic measures the time duration. If the flow time exceeds the allowance, a leak is suspected and the water is shut off automatically.   The system can have a local control panel or app-based control.
• Moen Flo Smart Water Monitor and Automatic Shutoff Sensor ($500) is an app-based product that “learns” your home appliances’ water usages and can shut off flow when leaks are detected through their FloSense technology.  The app is free with the product and the system is compatible with Amazon Alexa, Google Assistant, and Control4. 
• YoLink FlowSmart Control: Meter & Valve Controller, $40-1180, is an AC or battery-powered device (4 AA batteries) that monitors water usage and will shut-off water if flow exceeds pre-determined limits you set on the app.  This device requires a YoLink “hub” as it doesn’t connect directly to the app or your wi-fi.  

There are additional considerations as well.  Most of these valves are recommended to be installed by a licensed plumber.  You’ll also need to check what kind of battery backup they have so that in case of a power outage, you’re still protected from leaks.  If you don’t want wi-fi control, only one system (FloLogic) seems to have a local panel option instead of the app.  Despite these details, the time and money you spend on selecting such a system could be “a drop in the bucket” compared to costly renovations from water damage if you didn’t have this protection.  Busy lives and unattended homes need help to keep the water where it should be–in the pipes and drains!

Do HypoAir products kill the “good” bacteria as well as “bad” bacteria?

Short answer: yes, some good bacteria are killed, but let us explain a little about the nature of bacteria, and how this technology affects them!

Since HypoAir’s bipolar ionization is made for the home, we are talking about “good” bacteria for humans, found on exposed home surfaces, the skin, and upper respiratory tract, because this type of ionization does not penetrate to interior surfaces.

So the answer is: yes, bipolar ionization does kill some “good” bacteria, but the type of bacteria, on which surfaces, at what humidity, at what concentration of ions, and so on, are highly variable!   We find that the biological and air quality contaminants found in homes are typically in high unhealthy concentrations, which are typically not found in the outside air.   We want to reintroduce natural counterbalances to suppress the spread and growth of these biologicals indoors, to make them more similar to what's found in nature.  However, our technologies are not going to sterilize the environment; they're just designed to cut concentrations and reduce illness in families.  In 20-30 years, technologies like ours could become very cost effective and installed throughout a home to have a nearly sterilizing effect in our indoor environments.  We don't want that!  At that point, the intentional reintroduction of a positive biome would be advisable.  If you are concerned that the use of bipolar kills too many good bacteria, you may want to investigate probiotics for the air to replace those good bacteria on surfaces, and use gentle cleansers and soap for your skin, dispensed from containers that don’t promote the growth of bacteria.  And, consider the fact that pets (and dogs especially) vary the nature of your home’s microbiota a lot too!  

Getting back to bacteria, here’s a short refresher from an article about bacteria, endotoxins and exotoxins:  bacteria can be classed into two different groups: “Gram-negative” or “Gram-positive”.  These classes are based on a test developed by scientist Christian Gram in 1884, which differentiates the bacteria using a purple stain.   According to webmd.com, bacteria either have a hard, outer shell, or a thick, mesh-like membrane called peptidoglycan.  The hard outer shell will resist the purple stain, and show up as a red color.  These are called “gram negative” because the purple stain did not show.  Bacteria with the peptidoglycan absorb the purple stain much more easily and are called “gram positive”.  The stain also tells many more characteristics about the bacteria and the way it interacts with bipolar ions.

Bipolar technology is also called cold atmospheric-pressure plasma (CAP), or non-thermal plasma (NTP).  In a study which analyzed how plasma affected bacteria in soil, it turned out that the non-treated soil consisted of both gram-positive and gram-negative bacteria from different phyla (a level of classification).  After treatment with plasma, however, the gram-negative bacteria were mainly eradicated, and only the major phyla of Firmicutes (gram-positive) were left.  Presumably this has to do with the structure of the bacteria.

The authors cited two previous studies on treatment of E. Coli (gram-negative) and S. Aureus (gram-positive) with cold plasma.  In the first study, the treated Gram-positive bacteria was mainly inactivated by intracellular damage, while the Gram-negative bacteria expired mainly by cell leakage.  The second study showed that plasma treatment led to damage of the bacterial cell wall of both E. coli and S. aureus and a decrease in the total concentrations of nucleic acid and cellular protein. However, S. aureus (gram positive) was less susceptible to plasma exposure in comparison to E. coli (gram-negative).

The sum of these three studies seem to indicate that gram-positive and gram-negative bacteria are affected by plasma differently, and chances of survival of bacteria after treatment with cold plasma is higher if a bacteria is gram-positive, having more of the mesh-like membrane (peptidoglycan).  One can see from the diagrams below that these peptidoglycan layers are relatively thick on the gram-positive type, which may account for its resistance to plasma.  Depending on the relative humidity of the air, plasma can form varying quantities of reactive oxygen species such as hydroxide ions (OH-), hydroxyl radicals (•OH), atomic oxygen (O), hydrogen peroxide (H2O2), and singlet oxygen (1O2).   Ozone (O3) is another ROS formed by plasma generators, however we’ve excluded it from HypoAir ionizers by limiting the input energy.  These ROS are reported to damage the bacterial structure and functions.  In addition, the multiple reactive nitrogen species (RNS), including nitric oxide (NO), peroxinitrites (ONOO−), nitrites (NO2−), and nitrates (NO3−), can play a major role in the plasma’s biocidal process by altering the cell wall components, the functions and the structure of the phospholipid bilayer, the structure of nucleic acids and cellular proteins, gene expressions, and protein synthesis. (Effects of Atmospheric Plasma Corona Discharges on Soil Bacteria Viability)

Image source: Difference between gram-positive and gram-negative cell wall

However, there are factors other than gram-type that affect bacterial eradication via plasma technology, such as pH, humidity, and the surface on which the bacteria were placed during plasma exposure.  Specifically, 

• Lower pH can translate to higher kill rates.  A reduction of 4.9 log was observed when Bacillus cereus was treated at pH 5, while a reduction of only 2.1 log was observed at pH 7.  Interestingly, the same study showed that “No appreciable differences between gram-positive and gram-negative pathogens were observed, although the spore-forming B. cereus was more resistant to plasma than non-spore-formers.” (Spores in bacteria are not the same as mold spores; only one bacteria makes one spore). 
• Humidity was also reported as an important parameter; increasing the relative humidity was correlated to efficiency in plasma inactivation of Aspergillus niger, which was explained by the generation of more hydroxyl radicals. However, the same study showed that “In contrast, B. subtilis showed slightly poorer inactivation at high gas humidity.”
• Regarding the surface on which the bacteria were placed during plasma treatment, higher eradication was observed when microorganisms were loaded on a filter compared to a fruit surface, because the microbes could “migrate” to the interior of the fruit.  Therefore, if the bacteria could migrate into a moist surface, it was more likely to survive. (Cold Atmospheric Plasma Disinfection of Cut Fruit Surfaces Contaminated with Migrating Microorganisms)  Wow, bacteria can migrate! 

Now that we know that there are a lot of variables in your home that affect the mortality of bacteria, how likely is it that “good” bacteria on skin, your upper respiratory system, and home surfaces will be killed?

First of all, let’s look at what types of bacteria these are.  Staphylococcus epidermidis (phylum Firmicutes, gram-positive)  is a part of the skin microbiota (aka skin flora) and another type of good bacteria is Roseomonas mucosa (phylum pseudomona dota, gram-negative), which is naturally present on the skin and contributes to an overall healthy skin microbiome. (Dermatologists Break Down the Difference Between Good and Bad Bacteria)  In addition, the optimal pH value of skin on most of our face and body lies between 4.7 and 5.75, which is mildly acidic. (Understanding skin – Skin’s pH)  According to the studies above, it’s not known whether good bacteria on healthy skin survive plasma treatment, because although healthy skin is normally mildly acidic (which promotes their death by ions), moist skin favors preservation of good bacteria. Therefore, no matter what relative humidity is in your home, it’s a good idea to keep your skin hydrated!  

Concerning the upper-respiratory tract, potential keystone microbiota are Dolosigranulum and Corynebacterium species (both gram-positive), as they have been strongly associated with respiratory health and the exclusion of potential pathogens, most notably Streptococcus pneumoniae, in several epidemiological and mechanistic studies. (The microbiota of the respiratory tract: gatekeeper to respiratory health)  Regarding pH, airway surface liquid pH in normal airways ranges in vivo between 5.6 and 6.7 in the nasal mucosa, and is around 7.0 in bronchia.  (Airway Surface Liquid pH Regulation in Airway Epithelium Current Understandings and Gaps in Knowledge) Therefore it’s mildly acidic in the upper regions, and tending toward neutral pH in the lower regions.  Being gram-positive favors survival, as does being in mucous, but being on a mildly acidic surface favors eradication of these good bacteria.  Again, keeping your mucous membranes moist via water intake and plain saline sprays is a good idea!

Finally, most of the ions that are emitted by bipolar devices will contact surfaces in our homes.  What kind of good bacteria live on surfaces?  Forty homes in North Carolina were sampled for a study in August 2011.  Standard places like cutting boards, kitchen counters, door handles, toilet seats and pillowcases were sampled.  The bacterial families with the highest relative abundances across all of the collected samples were the Streptococcaceae (8.9%) (gram-positive), Corynebacteriaceae (5.6%) (gram-positive), and Lactobacillaceae (5.1%) (gram-positive).  Since these are all gram-positive, their survival would also depend upon the acidity and nature of the surface.  Keeping the humidity in the home in the sweet range of 40-60% will favor the production of more bacteria-killing hydroxyl radicals, and cleaning regularly is important.  Wet, dusty or cluttered surfaces will actually promote good bacteria survival, but they also promote bad bacteria survival too, so to play it safe, it’s best to keep surfaces clean!  

Is it ok to walk around barefoot in my home?  I’m concerned about my feet absorbing mycotoxins.

Often we end up researching and writing articles in response to client questions, and this is one such article.  If your floors are warm or carpeted, it often feels good to walk around barefoot in the house.  However, this may or may not be a good idea, depending on what is on your floors.  Can toxins really go into or out of your feet?

“Foot detoxing” pads, baths and creams have been popular for a while.  Usually they show the pad or water turning brown with “toxins” after supposedly releasing them from your body through the feet.  However, there have been very few studies on their effectiveness.  In a small 2012 study, the researchers sampled water from before and after foot baths with the popular IonCleanse device, as well as hair and urine samples.  They found no evidence to suggest that ionic footbaths help promote the elimination of toxic elements from the body through the feet, urine, or hair.   So, it’s unlikely that these methods are able to pull toxins out of the body.

However, some molecules can be absorbed through the skin (particularly the feet) into the bloodstream.   You can even “taste” with your feet; if you apply garlic to the soles of your feet in a plastic bag ala this video, you can taste it in your mouth between 15 minutes to one hour later.  This is because small, light molecules like allicin (the chemical released in freshly-cut garlic) can penetrate the skin and the bloodstream, traveling throughout your body.  Dimethyl sulfoxide (DMSO) is a chemical that has similarities to allicin and is very easily absorbed through the skin.  Part of the DMSO is transformed to the volatile metabolite dimethyl sulfide, which gives a characteristic garlic- or oyster-like smell when excreted through the lungs.  (Adverse reactions of dimethyl sulfoxide in humans: a systematic review)  Therefore, we are susceptible to chemicals that behave in this way.  Scientists and drug-researchers are constantly in search of chemicals that can deliver drugs more easily to the bloodstream, and therefore new “carriers” are of great interest.  

What about mycotoxins that may happen to be on the floors?  Can we get mycotoxin poisoning from walking around barefoot?   Although there’s no direct answer via testing, research on individual mycotoxins shows that they can be absorbed through the skin, so it’s reasonable to assume that they can be absorbed through the skin of the soles of the feet.  Since mycotoxin concentration on surfaces is highly variable, however, it remains to be seen whether concentrations sufficient to cause illness are present on floors. 

We found that a 2014 paper summarizing previous research on the absorption of the most common mycotoxins through skin and their effects, was most helpful.   This research documented mostly animal trials to determine toxicity, but there are also reports of workers who were accidentally exposed to these toxins.   The actual methods of damage incurred by these toxins can be quite complex, so we will spare you the details, but many of them cause oxidative stress that stimulate the immune system, triggering inflammation and cell damage.  Here are some examples:

• T-2 toxin, a member of the trichothecene mycotoxin family, is produced by various species of Fusarium fungus, which can infect corn, wheat, barley and rice crops in the field or during storage.  It’s infamous for allegedly being used as a bioweapon during the military conflicts in Laos (1975-81), Kampuchea (1979-81), and Afghanistan (1979-81) to produce lethal and nonlethal casualties. (CBRNE - T-2 Mycotoxins) T-2 toxin causes oxidative stress, which releases cytokines (proteins that help control inflammation in the body) that are thought to cause the death of the outer layer of skin cells (keratinocyte apoptosis).   T-2 mycotoxicosis can cause nausea, vomiting, diarrhea, leukopenia, hemorrhaging, skin inflammation, and in severe cases, death. (T-2 Mycotoxicosis)  The reported LD50 (amount which causes death in 50% of exposures) of T-2 toxin is approximately 1 mg/kg of body weight. (Medical Aspects of Chemical and Biological Warfare)
• Citrinin (CTN) is a product of several fungal species belonging to the genera Penicillium, Aspergillus and Monascus. To summarize, CTN under in vivo conditions has the ability to cause oxidative stress and ROS-mediated DNA damage in mouse skin upon topical exposure, leading to skin death.
• Patulin (PAT) is a toxic chemical naturally produced by several species of mold, especially within Aspergillus, Penicillium and Byssochlamys.  A single topical application of PAT to mouse skin generates ROS, which causes DNA damage in skin cells.  In small doses it causes death of the cells, but in larger doses it initiates tumor growth.
• Aflatoxins are products of  several types of Aspergillus molds, with AFB1 known as the  most potent teratogen (causing malformation of embryos), mutagen and hepatocarcinogen (causes liver cancer) of all aflatoxins. Like in the case of PAT, AFB1 may also cause skin tumors in mouse skin after long-term and higher-dose application.
• Ochratoxin A (OTA) is a fungal metabolite produced by Aspergillus ochraceus and Penicillium verrucosum. OTA is found in a variety of plant food products such as cereals. To summarize, a single topical exposure of OTA at the dose level of 20–80 μg/mouse (20-80 millionths of a gram, with a mouse weight of 40-45 grams, translates to 0.5-2.0 ppm) induces the production of ROS, resulting in the skin cell death. On the other hand, a single topical exposure of OTA at a dose level of 100 nmol/mouse causes significant enhancement of short-term markers of skin tumor promotion in mouse skin.

As you can see, the least effect of these mycotoxins is to cause skin cell death, but the worst effects are whole-body!  They are effectively absorbed through the skin.  However, is it reasonable to assume that they would be found on your floors, in a sufficient quantity to cause illness?  

All four of the family members and the dog tested positive for OTA and some for tricothecenes in their urine; they had health problems involving the upper and lower respiratory tract, headaches, neurocognitive deficits, and severe sinusitis. They had chronic sinusitis and nasal inflammation, and the isolation of bacteria (Pseudomonas and Acinetobacter) and molds (Penicillium and Aspergillus) from nasal secretions from the father and daughter is consistent with other cause and effect symptoms of mold exposure.  Even the dog suffered from 72 lesions, an ear mass and lipomas (which were surgically removed), in were found OTA and tricothecenes.  The mother gave birth to a daughter 3 months after moving out of the home, which had skin inflammation and discolorations because of being exposed to mycotoxins in the womb and via breastmilk.  

Therefore, we can conclude from this sad scenario that mold, bacteria and mycotoxins are a real concern in house dust when the home has water intrusion and mold issues.  There’s no way to know how much of the mycotoxins were inhaled versus absorbed through their skin, but of course young children are closer to the floor, often crawling and sitting on it, thus sitting in dust, stirring up dust, and breathing it in.  The dog obviously suffered from laying on the floor!  

According to IndoorScience, a reputable indoor air-quality testing company, 

• there are no guidelines for “acceptable” amounts of mycotoxins in house dust, 

• mycotoxin testing is much more expensive than standard mold testing, and 

• there are only a few labs that perform mycotoxin testing.   

However, if you have water intrusion or mold problems in your home that you suspect are causing health problems, mycotoxins or toxins from actinobacteria (see our article here) could very well be the culprit.  In these cases, solving the water intrusion problem and remediation and thorough cleaning will also remove the mycotoxins and bacterial toxins!  Here are some tips for maintaining a cleaner home from our related article: 

• Invest in a HEPA air cleaner to remove dust from the air

• Clean floors regularly with a HEPA vacuum and mopping (some appliances do both)

• Filter the air that comes into your home via window filters

• Change your HVAC filter regularly and even upgrade it if possible

• Try to remove your outdoor shoes at the door, and wear indoor shoes or slippers only in the home

• Minimize clutter, upholstery and carpets that can hold dust. 

These are also common recommendations of doctors and practitioners who see mold illness in their patients, because removing them from surfaces is helpful whether the toxins are inhaled or absorbed.  If you suspect water intrusion anywhere in your home (even in places you can’t see, like the crawlspace or attic),  of course you’ll need to address remediation in the moldy area pronto.  However, since you don’t know how air currents may be carrying dust and toxins into the living space, it’s a safe bet to also step up the cleaning and keep your shoes on!

To Vent or Not to Vent the Dryer Indoors?

This was a tricky question.  We understand that many people live in poorly planned homes where they are not allowed to make changes.  However, venting a dryer inside has a lot of disadvantages, even health dangers.  It all comes down to knowing that more than just “hot air” comes out of the dryer; this is why they are supposed to be vented to the outdoors.

First of all, NEVER EXHAUST A GAS (propane or natural gas) DRYER TO THE INDOORS.  This is absolutely a safety hazard, because the combustion gas exhaust (including carbon monoxide and NOx) are mingled with that hot air, and no filter is going to remove combustion gasses.  You would be poisoning your home air quality.  If you have a gas dryer and do not see a way to install a vent to outside, stop right here and either change out your dryer for an electric one (preferably a heat pump dryer, which does not require a vent), or move your gas dryer to a location where you can exhaust the vent outdoors (which would involve moving the gas line, too).  If your dryer is electric, you can keep reading.

So, let’s first talk about what is coming out of your dryer vent.  

1. Obviously, warm air is coming out, because, after all, if your dryer is not heating your clothes, it’s likely not drying them.
2. Water vapor:  This is where all the water from wet clothes goes–it evaporates and goes out the vent.  Majorly humid air here.
3. Dust: You might collect some lint from your clothing on the dryer screen, but a lot of fine dust goes right through the screen into the vent line and outside.  This is why, when dryer vent lines are not sealed well, or they come loose, the laundry room suddenly starts to become very dusty!  And, vent lines should be cleaned of dust periodically so that they don’t become a fire hazard.  

In the wintertime, it might be tempting to redirect that hot humid air back into your home to save some money on heating and humidification!  However, most people who do vent inside either don’t care about the air quality or don’t keep up with the maintenance needed to do it right.  Here are the ways that venting inside can go wrong: (Clothes Dryer Moisture Activity)

1. With no filtration, a lot of lint gets spread around in the laundry room (and surrounding rooms and even the rest of the home via the HVAC ducts).  If anyone in your home is sensitive to dust or prone to asthma, this is not acceptable.
2. With filtration, you may be putting the dryer vent under too much pressure to keep the air flow up. Low air flow can cause the dryer to run longer.
3. Low air flow and lint buildup in the dryer vent can cause a fire.
4. The laundry room (and the surrounding rooms) can get too warm when you run the dryer in summer.
5. The laundry room (and surrounding rooms) can get too humid and create a risk for mold when you run the dryer in summer, or anytime that the humidity in the home is already high.  For every load of laundry you dry, you are venting up to a gallon of water in condensation from your dryer. This will create a sauna in your laundry room, which can cause wood to swell, paint to peel, and mold to take hold.  (Eight Problems with Indoor Dryer Vent Kits)
6. Venting a dryer indoors is against code (illegal) in most states.
7. There have been documented complaints that the fine particulates of lint that escape from the reservoir can cause the smoke detector to go off.  This is proof that there are loads of  particulates coming through indoor drying vents. (Eight Problems with Indoor Dryer Vent Kits)

Needless to say, the problems with venting indoors are legion. 

We want to empathize with tough living situations.  Some people live in an apartment or home that has an improvised laundry cubby in the middle of the building, and the owners did not install a vent.  Unless the laundry room is sitting over a crawlspace or basement with an unfinished ceiling, it can be difficult to install a ventline to the outside, even if you have an agreeable landlord.  In many situations telling a landlord about the problem will not solve the issue.  Sure, there are lots of positive comments about “ventless dryer filters”, but many other users are not reporting the huge humidity problems in their laundry room after drying just one load.   For all these reasons and more, we want to be kind and say that indoor dryer venting is ok, but in the end the safety considerations outweigh it.

So, here are some options:

1. If you have the budget, plan to stay in your home a long time or are able to take a dryer with you when you move, consider purchasing a heat pump dryer (which is ventless).  
2. If the landlord is not willing to install a vent, but the room has a window that opens, explore the options of a Dryer Vent Window Kit ($30-37).  You may also want to add a window lock if you’re permanently installing it in a ground floor window.
3. OR, move the dryer to a room that has a window and run an extension cord to it, which would have to be plugged/unplugged every time you do laundry. 
4. Run an extra spin cycle on your wet clothing to wring out more moisture, and air dry clothing on a rack.
5. Offer to trade services with a friend who has a properly vented dryer (meal prep, car wash, dog walk, use your imagination!)
6. Take your laundry to a laundromat.  

Dryers and laundry rooms in general require more planning than you think!  We tried to be creative and make the most of a difficult situation.  If you have another alternative that works for you, we’d love to hear about it!